Incidence, Pattern and Severity of Adverse Events Following Immunization (AEFIs) Associated With Chadox1 nCOV-19 Corona Virus Vaccine (Recombinant) Among the Healthcare Workers of a Tertiary Care Institute of Eastern Uttar Pradesh, India.

Background In January 2020, the Government of India based on the recommendation of the Drugs Controller General of India (DCGI) and National Technical Advisory Group on Immunization (NTAGI) started the rollout of the COVID-19 vaccine in the country. Two vaccines, ChAdOx1 nCoV-19 coronavirus vaccine (recombinant), i.e., COVISHIELD produced by Serum Institute of India and COVAXIN developed indigenously by Bharat Biotech, were given emergency use authorisation (EUA) by the DCGI. Methods In this cohort study, we assessed the incidence, pattern and severity of adverse events following immunization (AEFI) observed among the healthcare workers of a large tertiary care institute in eastern U.P., India vaccinated with ChAdOx1 nCoV-19 Coronavirus vaccine (recombinant) within 30 minutes of vaccination by direct observation. Results Out of the total 836 healthcare workers who were vaccinated with the first dose of the vaccine, around 10% experienced any AEFI within the directly observed period. The most common AEFI was pain/tenderness at the injection site experienced by 59.3% of those who experienced any AEFI followed by headache/dizziness (35.3%), itching/rashes at the injection site (8.1%), nausea/vomiting (5.8%) and fever/chills (4.7%). The majority (95.3%) of the AEFIs observed were of minor severity with no serious AEFIs observed as per the WHO severity classification. Conclusion ChAdOx1 nCoV-19 Coronavirus vaccine (recombinant) is proven to be safe based on our findings as the majority of AEFIs observed were of minor grade only. However, the vaccine beneficiaries should be strictly observed for a minimum of 30 minutes at the vaccination site to look for any serious AEFI with arrangements to manage the same.